Safe construction



June 19, 1956 E. MCCLELLAN 2,750,902

SAFE CONSTRUCTION Filed Aug. 16, 1954 //2 Men for United States PatentSAFE CONSTRUCTION Ralph E. McClellan, Toledo, Ohio, assignor. to MeilinkSteel Safe Co., Toledo, Ohio, a corporation of Ohio Application August16, 1954, Serial No. 449,904

1 Claim. (Cl. 109-81) This invention relates to wall and safe featuresresistant to attack, especially in the guarding of contents againstunwarranted attack.

This invention has utility when incorporated in an inter wall of drillresistant properties, say of hard metal and alloys with the outer faceof such wall configured not to have symmetrical cutting arc, therebydetracting from hard steel drill heating or fusion action. This resultsin discontinuous grabbing at wall different regions as spaced, withtorque strains of such effectiveness as to break the tool.

Referring to the drawings:

Fig. l is a fragmentary horizontal section at the left hand corner of aone door safe, having features of the invention incorporated therein;

Fig. 2 is a sectional showing of a couple of ribs of the special faceproviding wall, with dotted line-showing of unsymmetrical drill approachthereto;

Fig. 3 is a sectional showing of such wall face of general sinuouscontour, with adjacent ribs of different arc radii;

Fig. 4 is a section thru adjacently dissimilar diameter cylindrical rodsin abutting weld assembly, wherein the adjacent faces as rising from theroot do not have the same are;

Fig. 5 is a section of the protective face wall, enlarged from itsshowing in the safe wall as extending inward from the door opening inFig. 1;

Fig. 6 is a fragmentary showing of the protective wall face with theadjacent pointed ribs, one more blunt than the other, instead oflop-sided as is the showing in Fig. 5;

Fig. 7 is a protective wall face showing of straight faced cones andconcave faced cones spacing the straight faced cones;

Fig. 8 is a showing of a wall face of rectangular pyramids whichalternately differing in side wall pitch; and

Fig. 9 is a fragmentary wall section of successive domes, theintermediate domes of lesser diameter having ogee arc sections towardtheir bases.

A safe body outer wall 1 encloses a filler or insulation 2. An innerwall 3 provides therein a safe interior 4. At a front opening 5 is adoor having an outside front wall 6, an inner wall 7 and a steppedconnecting frame 8 registering with a door jamb 9 connecting the wall 1with the wall 3. Combination lock spindle 10 is on the door front foroperating a lock 11 so that a handle 12 may throw lock-released boltmechanism 13, thus to clear the structure for outswinging of the door.Insulation filler 2 inside the safe door front wall 6 is clear of thelock 11 and the bolt mechanism due to a pan or interwall diaphragm 14.

Rivets 15 have clearance at openings 16 to mount a zigzag protectiveface structure 17. This face 17 on its side outward toward the wall 6has depressed regions, herein shown as V-bottomed grooves or valleys 18forming root portions from opposite sides of which rise projectingregion limits as the termini of diverging face portions 19, 20, atdifferent angles or pitches. In practice While there is adequate rangeto carry-thru these details of protective value, it is believed in pointto direct attention to the fact that diameter drill is normally maximumfor the tool for which the point 23 may be an obtuse angle of about 116or have a cutting edge less than about 35 with the plane of the plate orprotective face structure 17. Considering the drill to be of hard steel,driven at two hundred even up to five hundred revolutions per minute,and pressure exerted for the tool to enter the work, there is heatdeveloped from the frictional contact to heat the metal for filmstherefrom to be annealed and scraped off in drill progress. This is onthe basis that the work to be drilled is hard.

Should the material to be drilled be soft, this type of hard steel drillwill act upon the relatively soft metal for producing chips which adhereby weld action on the drill tip and cutting edges, thus nullifying itscutting action. However, here the protective wall selection is that suchwall, at least as to its face as outward from the safe interior, be heattreated, or the body he of hard stock. Accordingly, there is a hardnesswall in a range to require efficient operation thereupon of carbide andsuch range of hard steel type of material in drills. Such may range ofRockwell hardness A 82 to 94 and higher and extend into the not so hardRockwell scale C 61 to 64. This means that the protective wall face, asspaced inward from the safe outer wall, does not afford a continuouscontact area or closed figure face distributed as endless about thedrill tip. The high speed rotation, together with the applied pressure,cause the drill tip to develop, from such unbalanced resistance, lateralpushings or wedge actions. The fact that the rivets 15 allow theprotective plate 17 to shift or float, thus nullify lateral holding ofthe work to center with the drill. Supplementing this disturbance ofcutting action are the interruptions or successive grabbings of suchunbalanced resistances for taking on bites at the stock. As the drillcomes against a bite region from a clearway or gap, there is impedanceacting as a torque hammer reverse tending to twist the tool in its body,counter to its direction of rotation. These poundings or hammerings notonly tend to introduce internal crystallization, but actually rapidlydevelop drill rupture. The drill is thus soon disabled. Unauthorizedaccess to the lock or boltwork is not achieved when there is concealedin the safe structure discontinuous dissimilar face regions defeatingdrill entrance for peripheral cutting action endless orbits.

Various embodiments have to do with rendering effective nullification ofdrill operation. Economy in manufacture of the special face may be takeninto account by differing angle adjacent rib faces in an embeddedirregular corrugation body 17 (Fig. 2). In lieu of apex providing orlinear ribs, there may be sinuous contour of major rib 26 as to adjacentminor radius rib 27 (Fig. 3) from a common root or re-entrant region orgroove 28.

Weld connected rods 29, 30 (Fig. 4), are shown as even having pluraldepth root regions 31, 32. As with the fiat faces (Fig. 2) and the arcfaces (Fig. 3), there is dissimilar divergence of the faces as outwardfrom the re-entrant limit.

Stock having flat side 33 (Fig. 5) has such not outward, but on the facetoward the outer wall 1 (Fig. 1) has groove depth lines or roots 34,with dissimilar rise angle flat faces 35, 36, therefrom. Inner wall 3 isshown with a tongue 37 pushed out therefrom and overlapping an edge ofthe wall 33, 34, 35, 36 (Fig. 1) thereby providing a fastening loose inlieu of the rivet feature for locating the wall 17.

As a departure from the dissimilar slant divergent faces 35, 36 (Fig.embodiment as Wider base ribs spaced by ribs more narrow (Fig. 6) arehere shown as from a planar back 37, a root 38, steeper flat faces 39and less slant faces 40.

Departure from the rib and groove embodiments is in rows of cones 41,42, alternating with each other in the two directions and rising fromfiat base 43. From roots 44 straight face cone 41 sides take difierentascent from the dissimilar concave face side cones 42 (Fig. 7).

Interrupted or discontinuous peaks or points are provided by rectangularbase pyramids 45, 46, from a base 47, providing roots 48. The straightsides of the cones 46 are more steep than the sides of the cones 45(Fig. 8).

A base 49 (Fig. 9) has domes 50 spaced by less diameter domes 51 havingogee mergings to spacing regions, valleys or roots 52.

The protective wall or safe structure as herein disclosed is an embeddedply with the outward face portion of greater area than like dimensionsection of the enclos ing wall as directly outward therefrom. The areasurplusage of this face is development achieved by root depth regionsand dissimilar diverging faces rising therefrom linear or pointprojecting regions spaced by the irregular depth connecting regions. Inpractice this means that a rotary drill theretoward, when thrust toengage a pair of diametrical regions for tangency with two faces and gapor clearance spacings between said tangency regions, defines a plane. Asthere be drill pressure to act on the protective wall face, should therebe attack at each tangency, the dissimilar characteristic insures thatsuch attacks are of cutting arc departure, with differing peripheralresistance to the functioning of the drill. The drill torque isunsymmetrical twistings overcoming the physical or hold-togetherproperties of the tool, with resultant tool rupture almost at once thereis drillingattack on the ribbed or pimpled face.

Stock as superficially hardened, may have the interior thereof oftoughness to resist fracture or brittle traits as more prevalent in thetool, especially carbides and some alloys. Impact attack on the wall,even to the extent of developing fracture, has such wall protective.

What is claimed and it is desired to secure by Letters Patent is:

A drill resistant wall comprising a pair of relatively thin hard spacedshells with a relatively thicker and softer filler therebetween, theimprovement comprising: a hardened metal plate between said shells withsaid filler, at least one surface of said plate being irregular andhaving a plurality of alternate sharp projections and depressionsconnected by sloping surfaces having an angle of more than about 35 withthe plane of said plate, said sloping surfaces between two adjacentsharp projections having different slopes to their intermediatedepression, and means for fastening said plate in said wall to permitlimited movement thereof in the plane of said plate.

References Cited in the file of this patent Great Britain May 19, 1941

